In the field of medical photographic light-sensitive materials, in particular, high sensitivity and high image quality are essential requirements of patient disease diagnosis.
It is known to use tabular silver halide grains to achieve high sensitivity and high image quality. Tabular grains offer advantages such as improved spectral sensitization efficiency and improved image granularity and sharpness, and are disclosed, for instance, in British Patent No. 2,112,157 and U.S. Pat. Nos. 4,439,520, 4,433,048, 4,414,310 and 4,434,226.
However, tabular silver halide grains are faulty that fogging is likely when they are compressed. As means of overcoming this drawback, some methods have been proposed in which silver halide grains are prepared to have a core of higher iodine content or to incorporate a latex. However, the former approach does not offer a perfect solution because of pressure desensitization, resulting in nothing more than a balance between mutually opposite features called pressure blackening and pressure desensitization. The latter approach has drawbacks such as deterioration of the driability of the light-sensitive material upon processing because of the increased amount of binder.
Also, methods of eliminating the hardening in the course of processing are disclosed in Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) Nos. 111933/1983 and 206750/1988, in which tabular silver halide grains are used at a hydrophilic colloid layer swelling rate below 200%. In fact, the driability improves and the degree of hardening can be lowered when tabular grains are used at a hydrophilic colloid layer swelling rate of not higher than 200%. However, hardener-free processing results in an extremely increased number of roller marks, or roller pressure traces occurring in the developer, so that no satisfactory results are obtained solely by reducing the light-sensitive material swelling rate below 200%.